Supporters, opponents of gay marriage wait for a ruling on Proposition 8

Jeff Tabaco, left, and Thom Watson chat with a neighbor in front of their home in Daly City, Calif., Monday, June 10, 2013. The U.S. Supreme Court is expected to rule this month in a lawsuit that challenged the constitutionality of the gay marriage ban, known as Proposition 8. (AP Photo/Marcio Jose Sanchez)

Jeff Tabaco, left, and Thom Watson pose for a portrait outside of their home in Daly City, Calif., Monday, June 10, 2013. The U.S. Supreme Court is expected to rule this month in a lawsuit that challenged the constitutionality of the gay marriage ban, known as Proposition 8. (AP Photo/Marcio Jose Sanchez)

Thom Watson, right, and Jeff Tabaco show the rings which they exchanged during their 2009 wedding ceremony at their home in Daly City, Calif., Monday, June 10, 2013. The U.S. Supreme Court is expected to rule this month in a lawsuit that challenged the constitutionality of the gay marriage ban, known as Proposition 8. (AP Photo/Marcio Jose Sanchez)

Thom Watson, left, and Jeff Tabaco chat in their living room at their home in Daly City, Calif., Monday, June 10, 2013, next to a portrait of themselves they received during a 2009 wedding ceremony. The U.S. Supreme Court is expected to rule this month in a lawsuit that challenged the constitutionality of the gay marriage ban, known as Proposition 8. (AP Photo/Marcio Jose Sanchez)

Planning a party for thousands of people would be a challenge under the best of circumstances. Now imagine trying to pull off such a gathering without knowing what day it should happen or whether there even will be cause for celebration.

Such are the circumstances for same-sex marriage supporters as they await a United States Supreme Court decision that will determine whether California’s voter-enacted ban on gay marriages lives or dies. The high court’s ruling in a lawsuit challenging the constitutionality of Proposition 8 is expected before the end of the month, bringing with it the possibility that same-sex couples again will be able to wed in the nation’s most populous state.

The court’s justices heard oral arguments in the 4-year-old case in March. This month, as their summer recess nears, the justices meet every Monday morning to issue opinions and may schedule additional days for rulings, including one already set for tomorrow. But the court does not give advance notice of which decisions it will release when, leaving organizers of decision-day events being planned nationwide to watch, wait and plan for multiple scenarios.

“Not knowing what the day or the nature of the decision will be, everything feels like a placeholder,” said Stuart Gaffney, who along with his husband, John Lewis, is arranging a public rally in San Francisco. “From couples who would love to exchange their vows ceremonially that day to entertainers and even people who have equipment and sound systems, we can’t say with any certainty whether anyone can be there.”

Court watchers and legal experts are anticipating one of six possible outcomes: One could make bans on gay marriage unconstitutional nationwide; another would legalize gay marriage only in California and six other states that already provide the legal rights of marriage through civil unions or domestic partnerships; three other scenarios would allow same-sex marriages to resume in California itself.

The justices also could uphold Proposition 8, which would turn the planned parties into protests and prompt gay rights activists to seek to undo the ban at the ballot box next year.

“You prepare for every possibility, but there are so many roads to victory here that will lead to marriage equality back in California,” said Theodore Boutrous Jr., a lawyer for the two same-sex couples who sued to overturn Proposition 8 in 2009.

The ban’s supporters are not planning any formal events to mark the occasion, said National Organization for Marriage President John Eastman.

“We are, of course, quite hopeful that the court will not interfere with the right of the people to decide this very important issue of public policy,” Eastman said.

If gay marriage backers get the ruling they are hoping for, it is likely to take about a month before couples could start getting married in California, said San Francisco City Attorney Dennis Herrera. The losing side has 25 days under court rules to petition for a rehearing, and the decision would not become final until that period elapses.

California Gov. Jerry Brown, Attorney General Kamala Harris and state public health Director Ron Chapman, who while named as defendants in the case refused to defend Proposition 8 in court, might need a few days more to notify county clerks that same-sex couples seeking marriage licenses should no longer be turned away, said Herrera.

“We are just going to be prepared to do whatever we need to do if Prop. 8 is struck down, which we are confident it will be, to have all the resources available to effectuate the ruling and to let the marriages begin as quickly as they can,” he said.

Proposition 8, which amended the California Constitution to define marriage as the union of a man and woman, passed with 52 percent of the vote in November 2008, a little more than five months after the state Supreme Court had legalized same-sex marriages by striking down a pair of laws that also had limited marriage to opposite-sex couples.

During the brief window when same-sex couples could get married back in 2008 – an estimated 18,000 couples did – the state updated its marriage licenses to make them gender-neutral. The forms never were changed back to refer to a “bride” and “groom.”

“I don’t anticipate a big hiccup,” said Darling Allen. “We have already done this, so we can do it again pretty easily.”

Among those eagerly awaiting word from the high court are Thom Watson, 50, and Jeff Tabaco, 36, a Daly City, Calif., couple who are celebrating their 10th anniversary together this month. In 2009, they had a ceremony to acknowledge their devotion to each other, but they decided against marrying in another state while Proposition 8 was in effect.

Now, they’re making tentative plans for a wedding.

“California is our home, so we want to be able to marry here. That was the reason after Prop. 8 passed we decided to have a commitment ceremony,” Watson said.